1. Field of the Invention
The present invention relates to an improved hose reel, in other words, a reel for winding and unwinding a hose for transporting a medium, more particularly for the transport of compressed air from this reel by the hose being in connection therewith to a compressed-air tool.
2. Description of the Related Art
It is known that with a classic reel driven by a spring, when drawing off the air hose, a spring is wound. As soon as the hose is let loose, the aforementioned spring will provide the tension for rewinding the hose.
Such reels driven by a spring substantially show two important disadvantages.
A first disadvantage is that involuntarily letting go of the hose during winding or unwinding will lead to very dangerous circumstances, in view of the fact that the hose at such a moment will be wound up in a rapid and uncontrolled way.
Another disadvantage of such reels driven by a spring is that, due to the tensioning of the spring, the force necessary to draw off the hose increases as a larger length of hose is unwound, as a result of which such spring reels become unsuitable for applications with a high usage frequency such as, for example, in production lines, assembly lines and such, in consideration of the fact that they result in an unnecessary tiring of the users of such a reel.
Another disadvantage of the reel driven by a spring is that one always has to search for the blocking position thereof.
Also, motor-driven reels are already known which are provided with a friction coupling, which also leads to various disadvantages.
A first disadvantage of these latter reels consists in that the force which is necessary to draw off the hose is related to the height at which the reel is placed and the weight of the hose, such that with heavier hoses and/or larger heights of the reel, the friction coupling has to be tensioned in order to prevent a spontaneous dropping of the hose. By tensioning the friction coupling, however, the pulling force which is necessary to draw of the hose is significantly increased such that, even with a reel which is mounted lower, the force which is necessary to draw off the hose in most cases is experienced as too large.
Another disadvantage of motor-driven reels with friction coupling is that, due to wear and tear, the coupling regularly has to be readjusted. Such reels, thus, are not maintenance-free. The exact adjustment of the friction coupling requires a lot of time and knowledge. Furthermore, such couplings often are not easily accessible.
Still another disadvantage of known reels with friction coupling is that the automatic winding of the reel only starts when the user has placed his tools into the tool holder in the proximity of the reel which means that the user, during his movement towards the reel, has to step over the hose and therefore has to take care not to stumble, and at the same time has to take care that, during the automatic winding of the hose, the latter does not unexpectedly get behind the user and/or other objects.
Another disadvantage of certain reels with friction coupling consists in that the signal for winding the hose is given by means of a tool holder which is equipped with a detection mechanism, which has as a disadvantage that the winding procedure of the hose can be activated by a third party in an undesired manner.
Other known reels comprise an electromagnetic coupling, but these also show various disadvantages.
A first disadvantage of this latter known reel consists in that a fast jerk at the hose may lead to so-called "spinning", whereby the reel drum rotates rapidly and unwinds more hose than desired, as a result of which the hose will heap up and a crisscross of hose will occur which can hamper, if not block, the drive.
Still another disadvantage of such reels with electromagnetic coupling consists in that, with a complete uncoupling between drive and reel drum, the drum, due to its mass inertia, will remain rotating for a period of time and will drop an undesired length of hose, as a result of which a heap of hose is created, again with the risk of stumbling or such as a result.